异色瓢虫饲养密度对成虫获得率及繁殖的影响

异色瓢虫具有自残习性，在大量饲养中需根据此特性探索出适宜的密度来保证成虫获得率和卵的获得量。在室内测定了在100 mL饲养盒中以地中海粉斑螟卵为食物的异色瓢虫幼虫不同密度下的成虫获得率以及雌雄成虫不同配比时的产卵量。幼虫饲养时，一个饲养盒中平均最多获得7只成虫，随着初始虫量的增多，成虫获得率呈下降趋势，单头饲养的获得率最高。成虫饲养时，1雌1雄、2雌2雄和3雌3雄处理的指标呈规律性变化，虫量越多，产卵前期越短、产卵期越长，总产卵量越大，单雌日产卵量越小，后代的孵化率均达80%以上。4雌4雄处理虫量多，相互干扰，导致产卵前期长、产卵期短、产卵量少，孵化率低、雌性比低。2雌1雄处理与相同雌虫数量的2雌2雄处理相比，单雌日产卵量、总产卵量、后代孵化率、雌性比均低于2雌2雄处理。3雌1雄、3雌2雄处理与3雌3雄处理相比，结果亦然。雌雄等量比少雄的处理产卵多且优，但单雌产卵量、后代孵化率、雌雄性比以单对饲养最高。

Effect of Breeding Density on Adult Harvest and Fecundity of Harmonia axyridis Pallas

Harmonia axyridis Pallas is characterized by cannibalism, it is important to develop a suitable mass rearing density that can ensure high adult and egg harvest. To this end, the adult harvest rate at different H. axyridis larval densities provided with the eggs of Ephestia kuehniella Zeller in 100 mL box, and the amount of oviposition at different adult sexual rates were measured. From one box, 7 adults were harvested on average. The harvest rates generally decreased with the increase of the number (1, 3, 5, 7, 9, 11, 13 and 15) of H. axyridis larvae per box. In adults rearing for eggs using the treatments of 1♀×1♂, 2♀×2♂ and 3♀×3♂, with the increase of adult numbers, the pre-oviposition period decreased the oviposition period prolonged, and the total egg harvest increased, while the oviposition per female decreased. Egg hatching rates of the different adult sexual rates were all over 80%. In the 4♀×4♂ treatment, long pre-oviposition, short oviposition period, low oviposition, low hatching rate, and low offspring female ratio were observed. Compared with the treatment 2♀×2♂, the treatment 2♀×1♂ showed lower daily egg production, total egg production, hatching rate, and offspring female ratio. It was the same with the treatments 3♀×1♂ and 3♀×2♂ when compared with the treatment 3♀×3♂. Our results indicate that the treatments with equal number of males and females are of higher egg harvest than those treatments with fewer males, with the individually paired adults showing the highest egg harvest, hatching rate and offspring female ratio.